1. Field of the Invention
This invention relates to a nacreous pigment containing a dye, which has an excellent brightness, a high chroma, a wide variety of color, a high color concentration, and also possesses high safety and excellent stability. The invention also relates to a cosmetic composition comprising said pigment.
2. Description of the Background
Nacreous pigments have widely been used in order to provide various products with gloss such as pearl- or gold-like gloss and the like. Such products include cosmetics, paints, plastics, inks, colors, miscellaneous goods for daily use, ornaments, and the like. Natural fish scale leaves, bismuth oxychloride, titanium mica, and the like are usually used as a nacreous pigment. From the view point of light resistance, stability, safety, dispersibility, gloss effect, cost performance, and the like, titanium mica is widely used.
Titanium mica can be prepared, for example, by the method described in Japanese Patent Publication No. 25644/1968. The titanium mica disclosed therein is such that is coated with titanium dioxide on the surface of mica particles. Interference colors of silver, gold, red, blue, green, or the like can be obtained depending on the amount of titanium oxide coated. Nevertheless, the external color actually observed is almost white, and different from these interference colors. In the method of this publication, externally distinct color cannot be obtained, although excellently pearly luster is obtainable.
There have been some attempts to obtain various external colors by using general organic or inorganic color pigments mixed with titanium mica. However, since titanium mica has a scaly form and its particle size is much larger than that of ordinary pigments, simple mixing of these pigments with titanium mica entails various problems. For instance, it is difficult to mix titanium mica uniformly with an ordinary pigment because of the differences in their particle size, specific gravity, shape, and surface properties. When mixed, separation is apt to take place, resulting in color bleeding.
To obtain a nacreous pigment having an excellent external color, therefore, a method of making a complex of titanium mica and an ordinary inorganic or organic pigment has been developed.
For making a complex of an inorganic pigment and a nacreous pigment, there are known methods including: (1) the surface of a nacreous pigment is coated with iron oxide, nickel oxide, cobalt oxide, copper oxide, chromium oxide, or the like, which possesses its own color (Japanese Patent Publication No. 25644/1968); (2) a nacreous pigment is coated with a precursor material of Prussian blue, which is then treated to convert into Prussian blue on the surface of the nacreous pigment (Japanese Patent Laid-open No. 46331/1978). These methods, however, have drawbacks including limitation to the color of the inorganic pigment, insufficient distinctness, unavailability of a color of high concentration, and the like.
On the other hand, for making a complex of an organic pigment and a nacreous pigment, there are conventionally known methods such as a method of causing an aluminum hydroxide layer to adhere to the surface of a nacreous pigment, followed by fixing of a dye on the surface of the nacreous pigment using the dye having a chelating agent and a group capable of forming a salt of very low solubility (Japanese Patent Laid-open No. 17910/1976; a method of fixing D & C Red No. 30 on the surface of a nacreous pigment using various methods (Japanese Patent Laid-open No. 169716/1987), and the like. These methods, however, have drawbacks including limitation to the color of the inorganic pigment, insufficient coloration, unavailability of a color of high concentration, and the like.
The present inventors made extensive and earnest studies to solve the above problems and, as a result, found that a nacreous pigment containing a dye, which has an excellent distinctness, a high color concentration, and which does not entail color bleeding when used, could be obtained by coating an insoluble salt of an acid dye and a basic aluminum salt on the surface of a nacreous pigment having an interference color. The inventors also found that a cosmetic composition comprising said nacreous pigment containing a dye possessed excellent external distinctness and luster. These findings have led to the completion of the invention.